SENSITIVITY OF NEW-GENERATION COMPUTED-TOMOGRAPHY IN SUBARACHNOID HEMORRHAGE

Objective: To determine the sensitivity of the initial new-generation CT (NGCT) scan interpretation for detection of acute nontraumatic suba rachnoid hemorrhage (SAH) and to decide whether lumbar puncture (LP) s hould follow a ''normal'' NGCT scan. Methods: A retrospective chart re view was performed of patients admitted between March 1988 and July 19 94 with proven SAH. Exclusion criteria were age <2 years, diagnosis ot her than acute SAH, history of head trauma within 24 hours before symp tom onset, NGCT scan not done before diagnosis, and records not availa ble, Patients were placed into two groups: symptom duration <24 hours (group 1) and >24 hours (group 2) prior to CT scan. The resolution of each NGCT scanner was recorded. An NGCT scanner was defined as a third -generation scanner or more recent. Results: Of 349 SAH patients, 181 met inclusion criteria. The sensitivity of NGCT scans for SAH was 93.1 % for the group 1 patients (n = 144) and 83.8% for the group 2 patient s (n = 37). The overall sensitivity was 91.2%, All the patients who ha d SAH not detected by NGCT scans were diagnosed by LP. There was no si gnificant relationship between NGCT scanner resolution and sensitivity for SAH. Conclusion: Initial interpretation of NGCT scans to detect S AH does not approach 100% sensitivity, A ''normal'' NGCT scan does not reliably exclude the need for LP in patients who have symptoms sugges tive of SAH.